Chronic stimulation drives human NK cell dysfunction and epigenetic reprograming
Aimee Merino, … , Jeffrey S. Miller, Frank Cichocki
Aimee Merino, … , Jeffrey S. Miller, Frank Cichocki
Published June 18, 2019
Citation Information: J Clin Invest. 2019;129(9):3770-3785. https://doi.org/10.1172/JCI125916.
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Research Article Immunology

Chronic stimulation drives human NK cell dysfunction and epigenetic reprograming

Abstract

A population of NK cells expressing the activating receptor NKG2C and the maturation marker CD57 expands in response to human CMV (HCMV) infection. CD3–CD56dimCD57+NKG2C+ NK cells are similar to CD8+ memory T cells with rapid and robust effector function upon restimulation, persistence, and epigenetic remodeling of the IFNG locus. Chronic antigen stimulation drives CD8+ memory T cell proliferation, while also inducing genome-wide epigenetic reprograming and dysfunction. We hypothesized that chronic stimulation could similarly induce epigenetic reprograming and dysfunction in NK cells. Here, we show that chronic stimulation of adaptive NK cells through NKG2C using plate-bound agonistic Abs in combination with IL-15 drove robust proliferation and activation of CD3–CD56dimCD57+NKG2C+ NK cells, while simultaneously inducing high expression of the checkpoint inhibitory receptors LAG-3 and PD-1. Marked induction of checkpoint inhibitory receptors was also observed on the surface of adaptive NK cells cocultured with HCMV-infected endothelial cells. Chronically stimulated adaptive NK cells were dysfunctional when challenged with tumor targets. These cells exhibited a pattern of epigenetic reprograming, with genome-wide alterations in DNA methylation. We believe our study has important implications for cancer immunotherapy and propose that exhausted NK cells could be targeted with inhibitory checkpoint receptor blockade.

Authors

Aimee Merino, Bin Zhang, Philip Dougherty, Xianghua Luo, Jinhua Wang, Bruce R. Blazar, Jeffrey S. Miller, Frank Cichocki

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Figure 5

Chronically stimulated adaptive NK cells expressing LAG-3 exhibit impaired IFN-γ production.

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Chronically stimulated adaptive NK cells expressing LAG-3 exhibit impair...
CD3/CD19-depleted PBMCs from HCMV-seropositive donors were cultured for 7 days with 10 ng/ml IL-15 and IgG2b isotype Ab, anti-NKG2A/C Ab, or anti-NKG2C Ab. (A) Representative FACS plots and summary data of intracellular IFN-γ levels in preculture CD3–CD56dimNKG2C– and CD3–CD56dimNKG2C+ NK cells cocultured with K562 targets at an E/T ratio of 2:1 (n = 4). Results are from 2 independent experiments. (B) NK cells after culturing were used as effectors in functional assays with K562 targets at an E/T ratio of 2:1. Shown are representative FACS plots and summary data of IFN-γ production by NK cell subsets stratified by NKG2C and LAG-3 expression (n = 4). Results are from 2 independent experiments. *P ≤ 0.05, by paired t test to compare LAG-3– and LAG-3+ NK cells in each condition.